Torque resistant security casing for a padlock

ABSTRACT

A security lock and encasement providing resistance to torquing moment with a slip ring designed to slide onto the padlock encasement from the back without being able to advance beyond the front face of the encasement. Said slip ring is designed such that it can only be applied or removed to the lock casing from the back of the casing and is properly aligned with said encasement through a setscrew that will break if sufficient torque is applied.

This application is a Continuation-In-Part of a Non-Provisionalapplication filed on Dec. 11, 2000 now ABN having U.S. application Ser.No. 09/734,491, the priority of which is claimed.

BACKGROUND

1. Field of the Invention

The present invention relates generally to the field of padlocks, andmore specifically to a torque-resistant protective case enclosing a lockand a shackle.

2. Prior Art

While padlocks generally provide a measure of security for articlesbeing protected, they have not been a completely effective deterrent inoutdoor areas prone to vandalism or in areas requiring higher securityagainst that kind of destructive activity. In most applications, acommon padlock is vulnerable to cutting tools that can cut the shackleor to other tools, such as a pipe wrench, that can break the shackle,hasp or lock through torque. Historically, the shackle has been the mostvulnerable portion of the padlock.

A development towards protecting the shackle was seen in U.S. Pat. No.3,835,675 issued to Lippisch. Lippisch extended the encasing portion ofthe lock to cover a portion of the shackle. However, this design stillleft the shackles partially exposed and accessible to cutting tools.Thus, this device provided only a small amount of additional securityover existing technology.

Further technical advances came when the entire lock and shackle wereenclosed in a cylindrical casing. The casing caused the shackle to becovered when the lock was in use and attempted to prevent access to theprotected object via cutting the shackle. Several fully encased padlocksare known in prior art. These generally include a hard, fixed casingthat completely covers the shackle and are described in U.S. Pat. No.6,338,261(Liu) and U.S. Pat. No. 5,345,794 (Jenks), incorporated hereinby reference.

These designs solved the security problem that was caused by partiallyexposed shackles. However, because the design of the padlock called forthe casing to be rigidly affixed to the lock, it left the lock, hasp orshackle vulnerable to attack by the application of torque, through apipe wrench or other similar instrument. Thus, the new lock design fullyenclosing the shackles was only marginally effective in deterringvandalism.

In further developments, guards and encasements were added to negate thetorquing problem. The “guard approach” generally involved a guard thatcovered the approach to the lock, but was not integrated into the lockencasement (U.S. Pat. No. 5,172,574 to Perfetto and U.S. Pat. No.5,469,722 to Ellefsen). A rotating encasement approach is exemplified inU.S. Pat. No. 3,820,360 (Best) or U.S. Pat. No. 5,669,255 (Albano),showing a freely rotating encasement. This approach addressed thetorquing problem, but left the lock subject to vandalism because therotating encasement could be easily rotated to a position where thekeyhole was covered and then the encasement affixed to that position.Additionally, the freely rotating design often left the keyhole and theencasement hole misaligned, causing an inconvenience to the lock user.

However, none of the prior art has resolved the problem of protectingthe hasp, which is the weakest part of the lock protection. The problemwith breaking the hasp to gain entry into a locked object is that 1)unauthorized entry is allowed and 2) the process damages the thing to beprotected. Thus, as vending machines become more expensive, it becomesincreasingly important to protect them from damage through unauthorizedentry.

Therefore, what has been needed is a padlock that is resistant tocutting, resistant to the application of torque and easy to install anduse.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, a padlock is described that isresistant to attach through the application of torque and is easier touse than prior art. In the preferred embodiment, a locking mechanism ishoused in a cylindrical casing that encloses the locking mechanism andpartially encloses the lock's shackles. The sidewall of the casing iscovered by a slip ring to prevent the destruction of the lock throughrotational force. When affixed to the casing, the slip ring is preventedfrom forward axial movement by the cooperation of offsetting outerdiameters of the lock casing and the inner diameters of the slip ring.It is prevented from axial movement backwards in part by the fact thatthe back surface of the lock assembly abuts an immovable surface. Wheninstalled, the slip ring is inhibited from further rotational movementby a small setscrew or similar device that breaks with the applicationof sufficient torque. The location of the setscrew and threaded openingto receive the screw aligns the keyhole opening of the slip ring withthe keyhole opening of the casing, thereby making the lock easier touse.

To date, the lock has been extremely well received in the marketplaceafter independent testing because of the lock's ability to prevent entryby breaking the hasp. In testing in high crime areas, the inventionclaimed herein proved to be the only lock that did not succumb tovandalism and/or attack. Prior art lock technology in these areas hadbeen inadequate to prevent vending machine vandalism.

It is therefore an object of the present invention to provide a lockthat both protects the shackles and secures the lock against breakage bytorque.

It is a further object of the present invention to provide a lock thatis resistant to torque forced tampering through the use of a rotatableencasement/slip ring.

Further features and advantages of the present invention will beappreciated by reviewing the following drawings and detailed descriptionof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the objects and advantages of the presentinvention, reference should be made to the following detaileddescription, taken in conjunction with the accompanying drawing(s), inwhich like parts are given like reference numbers and wherein:

FIG. 1 presents a perspective, from the front, of the lock casing andthe slip ring;

FIG. 2 presents a the rear elevations of the slip ring and lock casingof FIG. 1;

FIG. 3 presents the side elevation of the encasement and the sideelevation of the slip ring;

FIG. 4 presents a perspective of the lock casing and slip ring as theywould be positioned onto a latch; and

FIG. 5 presents a perspective, from the rear, of the lock casing and theslip ring.

DETAILED DESCRIPTION OF THE INVENTION

A novel torque-resistant security casing for a secure lock is described.In the following description, for the purposes of explanation, specificcomponent arrangements, constructions and other details are set forth inorder to provide a more thorough understanding of the present invention.It will be apparent to those skilled in the art, however, that thepresent invention may be practiced without these specific details. Inother instances, well known manufacturing methods and structures havenot been described in detail so as not to obscure the details of thepresent invention unnecessarily.

Referring to FIG. 1, a lock generally referred to with numeral 10 (notshown) is enclosed within a cylindrical padlock casing 12 having a frontface 14, a rear face 16 and a sidewall 18. The sidewall 18 of the casing12 has a first larger diameter 20 and a second smaller diameter 22. Thefirst and second diameters 20, 22 combine with circumferencedifferentials within the slip ring 30 to prevent further forward axialmovement of the slip ring 30 when the slip ring 30 is placed onto thecasing 12 in a rear to forward axial movement. Because of the differingcircumferences of the lock casing 12 and the slip ring 30, the slip ring30 is unable to slide onto said casing 12 in a forward to rear axialmovement. In the embodiment shown, the circumferences 20, 22 arepositioned towards the rear edge of the sidewall 18. In an alternativeembodiment, the differential circumferences 20, 22 are positionedtowards the front edge of the sidewall 18. While size is not a limitingfactor in the invention, the preferred embodiment lock casing 12 has adiameter of approximately four inches. The material composition of thecasing 12 is not a limiting factor of the invention either. However, inthe preferred embodiment, the casing 12 is made of case hardened steel.

Referring next to FIG. 2, the front face 14 of the casing 12 is circularand has solid surface without any openings. The rear face 16 of thecasing 12 is circular and has a slightly smaller circumference than thefront face 14. The rear face 16 also has an oblong shaped shacklecut-out 40 in the opening to the rear face 16 of the casing 12 to allowa single I-shaped shackle 42 to project vertically within the shacklecut out 40. The casing 12 surrounds and encloses the locking mechanism(seen as an outlined figure in FIG. 5), which is rigidly affixed insidethe casing 12. The casing 12 has a cavity (not shown) extending inwardfrom the sidewall 18 (best seen in FIG. 1) to allow for the placement ofa keyed tumbler cylinder locking mechanism. The keyed tumbler lockingmechanism is maintained within the cavity (not shown) of the casing 12and includes a shackle 42 and a lock housing (not shown). The shackle 42is a single I-shaped shackle that projects from the bottom of theshackle cut out 58 upwards through the top of the shackle cut out 56. Aslip ring 30 encircles the lock casing 12.

Referring next to FIG. 3, the hollow, cylindrical slip ring 30 isslightly larger in diameter than the casing 12 and slides axially overthe sidewall 18 of the casing 12. The slip ring 30 has a third insidediameter 32 that corresponds to the first and larger outside diameter 20of the sidewall 18 of the casing 12. The slip ring 30 also has a fourthinside diameter 34 that corresponds to the second outside diameter 22 ofthe sidewall 18 of the casing 12. When the lock 10 is fully assembled,the first and second outside diameters 20, 22 of the casing 12 cooperatewith the third and fourth inside diameters 32, 34 of the slip ring 30prevent forward axial movement of the slip ring 30 when the slip ring 30is coupled onto the casing 12.

Referring now to FIGS. 4 and 5, the casing 12 also has a smallerthreaded opening 44 in the sidewall 18 of the casing 12 for a setscrew60 to act as an alignment guide to align to casing 12 keyhole 46 withthe slip ring 30 keyhole cut out.

The sidewall 18 of the padlock case 12 contains means for aligning thecasing 12 keyhole opening 46 with the slip ring 30 opening. The setscrew60 additionally prohibits the lateral movement of the slip ring 30 byaffixing the screw 60 through the slip ring 30 and into a threadedopening 44 in the encasement 12.

In one embodiment, the lock 10 has a shelf 48 that extends backwardsfrom the rear face 16. In an alternative embodiment, the rear face 16has a planar surface.

The lock is assembled by coupling the slip ring 30 to the casing 12 bysliding the slip ring 30 axially from the rear of the casing 12 towardsthe front of the casing 12. When the differing diameters of the slipring 30 and casing 12 meet, further forward axial movement of the slipring 30 is prohibited. The slip ring 30 properly aligns with the casing12 by inserting the setscrew 60 into the setscrew opening 44. The lockattaches to the device to be locked by sliding the lock axially towardsthe hasp 52 until the rear face 16 of the lock abuts the planar surfaceof the device to be locked. When the lock is fully assembled and in use,the slip ring 30 covers the sidewall 18 of the casing 12, the rear face16 of the casing 12 abuts the exterior wall of the item being locked,and the shackle 42 of the lock 10 attaches vertically to the hasp 52 ofthe item to be covered. When the lock 10 is engaged, the shackle 42passes through a hasp 52 that is firmly affixed to the item beingsecured.

In this manner, the casing 12 and slip ring 30 are properly alignedthrough the use of the setscrew and the lock 10 remains free fromvandalism caused by the use of rotational/torque force.

The description of the present invention has been made with respect tospecific arrangements and constructions of a lock that is resistant tobeing broken through torque or rotational movement. It will be apparent,to those skilled in the art that the foregoing description is forillustrative purposes only, and that changes and modifications can bemade to the present invention without departing from the overall spiritand scope of the present invention. The full extent of the presentinvention is defined and limited only by the following claims.

1. A lock comprising: a cylindrical lock encasement including; a frontface; a sidewall; a rear face having a rounded rectangular shapedopening extending inward for less than the width of said sidewall forreceiving a shackle and a hasp, said shackle designed to couple withsaid hasp attached to a device to be locked; a cavity extending inwardfrom the surface of said sidewall towards the center of said encasementand adapted to receive a tumbler keyed locking mechanism; said sidewallhaving; an opening adapted to receive a tumbler keyed locking mechanismand opening into said cavity; a threaded opening for receiving asetscrew; a circumferential groove passing over said threaded opening; afirst and a second diameter; a slip ring capable of coupling to saidencasement by sliding axially from the rear to the front of saidencasement, having; an opening for allowing a key to be inserted intosaid tumbler keyed locking mechanism; an opening for allowing saidsetscrew to be received into said threaded opening for said setscrew;said setscrew opening and said threaded opening located with respect tosaid sidewall opening and said slip ring opening such that insertingsaid setscrew aligns said sidewall opening over said slip ring opening;a third inside and fourth inside diameter; wherein said lock isresistant to torque force by the use of said slip ring axially attachedto said case and said forward axial movement of said slip ring isprecluded past said front face through the use of differentcircumferences on said sidewall and within the inside diameter of saidslip ring.
 2. The device of claim one wherein said rear face of saidcylindrical encasement has a shelf in the upper one-half of saidencasement that extends rearward beyond the planar surface of a lowerone-half of said rear face such that a portion of said rear face canrest on a ledge surface with the remainder of said cylindricalencasement hanging over said ledge surface.
 3. The device of claim onewherein; said first diameter of said sidewall is positioned towards thefront face of said lock casing; said second diameter of said sidewall ispositioned towards the front face of said lock casing; said thirddiameter of said slip ring is positioned towards the front of said slipring; and said fourth diameter of said slip ring is positioned towardsthe front of said slip ring.
 4. The device of claim one wherein; saidfirst diameter of said sidewall is positioned towards the rear face ofsaid lock casing; said second diameter of said sidewall is positionedtowards the rear face of said lock casing; said third diameter of saidslip ring is positioned towards the rear of said slip ring; and saidfourth diameter of said slip ring is positioned towards the rear of saidslip ring.
 5. The device of claim one wherein said rear face of saidcylindrical encasement has a shelf in the lower one-half of saidencasement that extends rearward beyond the planar surface of said upperone-half of said rear face such that a portion of said rear face canrest on a ledge surfaces.